I have a Ubuntu 20.04 LTS server with many LXD/LXC inside that work from webserver with WordPress or HTML Website.
Exist an antivirus that can read the LXD/LXC or do you have to install the system in each container?
You could potentially use lxc file mount to mount the container’s filesystem locally and then run the AV scan on that. I’m not sure what the performance would be like though as it may copy some/all of the file contents temporarily to read it.